Various types of load bearing industrial machinery include solid tires, the most common of which are forklift trucks. Unlike inflated tires, solid tires have an outer peripheral solid flexible layer, such as solid rubber, bonded to an inner cylindrical metal band. The tire is mounted upon a cylindrical hub wherein the outer cylindrical surface of the hub is press fit within the inner cylindrical surface of the metal band. The band is slightly stretched during press fitting and therefore the hub and tire are securely connected without the need for mechanical connectors or welding. Hydraulic presses are used to separate and connect the tires and hubs during regular maintenance and tire replacement.
In order to increase lateral stability of a fork lift for example, or increase the tire bearing surface for load distribution or traction increasing purposes, machine operators often install solid tires of width greater than the width for which the machine was designed and greater than the width of the hub. It is, of course, possible to replace an existing hub with one of greater width to accommodate the wider tires. However, hubs are relatively expensive and other associated machine parts such as brake drums, axles, etc. may be required to complete such a conversion. The least expensive and most common approach to install overwidth tires on a standard hub and replace prematurely worn or damaged tires as required. The need to replace worn tires as an operating expense is usually not questioned by supervisors, whereas the need to replace substantial machine parts such as hubs involves a capital expenditure which must be justified.
Such overwidth tires may have a 1 or 2 inch outer portion of their width which is unsupported and extends beyond the hub. The unsupported outer portion is exposed to impact loads as the vehicle tire collides with obstacles or is driven over uneven surfaces. The outer portion of the tire band may be bent or dented and the bond between the band and flexible solid rubber surface broken resulting in premature tire failure.
To reinforce the unsupported outer portion of the tire band, it is known to install a reinforcing ring adjacent the hub to support the internal diameter of the band. To secure such conventional reinforcing rings in place, the ring is welded to the tire band. The heat from welding may cause the bond between the solid rubber tire surface and tire band to break leading to premature tire failure. Welding the ring effectively forces one to either dispose of the ring with the worn tire or to gouge and re-weld the ring during replacement. Bolting the ring to the hub involves drilling of the hub thereby weakening the hub, and may be impractical due to interference of connecting bolts with adjacent machine parts. Both welding and bolting of the ring therefore involve separate additional operations during tire replacement. Welding in particular requires additional equipment which may not be readily available to service personnel and involves a skill that may not be common to the trade.